The invention relates to a machine for fabricating a reinforcing body for a concrete pipe, wherein the reinforcing body consists of longitudinal rods and of wires wound over the latter and welded thereto at the intersections. Machines are known for this purpose in which a stationary main wheel and an axially mobile support wheel are provided. The wheels are mounted coaxially and are drivable synchronously. The main wheel carries radially adjustable guide pieces which serve as welding supports for the longitudinal rods. A first servomotor is provided for the common uniform adjustment of the guide pieces. A welding carriage is moved transversely to the longitudinal axis of the machine by means of a second servomotor which operates in synchronism with the first servomotor. A welding apparatus, which executes welds at the intersections consecutively during the rotary movement of the main wheel, is mounted on the welding carriage.
Such a machine is disclosed in German Offenlegungsschrift No. 2,946,297 and corresponding U.S. Pat. No. 4,365,657. In this case traction cables, returned in the longitudinal direction by means of pulleys and driven in common by a first cylinder arranged axially behind the main wheel, are provided for the radial displacement of the guide pieces. The first cylinder, and a second cylinder which moves the welding carriage, are constructed and connected hydraulically as synchronous cylinders.
In the case of this known machine it is possible for the guide pieces and the welding apparatus to be adjusted continuously and in synchronism along the total radial stroke existing in the case of a main wheel of a definite diameter. It is thereby possible to consecutively fabricate circular reinforcing bodies, often referred to as reinforcement cages, of different diameters, without waste of time for converting the machine to a new diameter. It is also possible to shape a socket onto the substantially cylindrical-shaped reinforcing bodies, so that the resulting concrete pipes can be plugged into each other.